Lifting-jack.



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J. CA, nwELL.

LIFTING JACK' www.

Patented July lo, mo. J. CALDWELL. A Y* LIFTING JACK.

(Application led Mar. 10, 1899.; (No Model.)

Inl/niark 1 By M 7%4 A STATES PATENT CEEICE,

JACK CALDWELL, E KANSAS CITY, MISSOURI, AsSIeN'oE CE CNE-HALE To CHARLES HOWARD, CE SAME PLACE.

LlFTlNG-JACK.,

SPECIFICATION forming part of Letters Patent No. 653,283, dated July 10, 1900.

Application filed MMG-i1 10, 189,9.

T0 all whom, t may concern.-

Be it known that I, JACK CALDWELL, of Kansas City, Jackson county, Missouri, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is a specification.

My invention relates to lifting-jacks, and more especially tothat class wherein an intermeshing worm shaft and wheel are adapted to raise and lower a vertical screw engaging internal threads on the wheel, accordingly as the latter is turned in one direction or the other and one object is to produce a liftingjack of this character and of simple, comparatively-cheap, Small, and compact construction, with great capacity for lifting.

Other objects will hereinafter appear; and the invention Consists in certain novel and peculiar features of construction and combinations of parts, as will be hereinafter described and claimed.

In order that the invention may be fully understood, reference is to be had to the accompanying drawings, in which- Figure 1 represents a vertical central section of a lifting-jack embodying my invention. Fig. 2 is a view, partly in horizontal section and partly in plan, the cover-plate being omitted. Fig. 3 is an irregular section taken on the line Ill III of Fig. 4. Fig. 4 is a section taken at right angles to the Section shown in Fig'. 3. Fig. 5 is a horizontal section taken on the line V V 0f Fig. 1.

In the said drawings, 1 designates the heavy cast-metal base or stand of the lifting-jack, said base being cast with ahandle 2 and with a circular chamber 3 and an offsetting chamber 4, the latter being formed in the rectangular enlargement 5, provided at one end with a journal-opening 6 and at its opposite end with a threaded opening 7, said openings being axially alined. 4 Theend wall of said enlargement having the journal-opening is provided with a channel or groove 8 in its inner side, and concentrically surrounding the opening G and seated in said channelare the antifriction-balls 9, hereinafter more particularly referred to. The base of the chamber 3, concentrically thereof, is formed with a groove 10,l semicircular in cross-section, and seated `Serial No. 708,584. (No model.)

therein are antifriction-balls l1 of compaia tivelydarge size.

12 designates a Worin-wheel having its periphery channeled out or grooved and having its teeth 13 of segmental form for a purpose which will presently appear. The hub 14 of each wheel has an annular groove 15, Within which projects the retaining-Screw 16, mounth ed in the base or stand and adapted to prevent `any upward movement of said wheel, the latter being also provided in its under side with a groove 17, engaged by the antif friction-balls 11, hereinbefore referred 'to. The hub is internally threaded, as at 18, and provided with one or more inclined oil-passages 19in order that a lubricant, preferably castor-oil, poured in the chamber 3 may pass down through saidpassage and thoroughly lubricate the vertical screw 20, engaging thread 18 of the worm-wheel. Said Screw is provided With an enlargement` or head 21, having its upper surface preferably roughened, and below said head with a pair of holes 22, extending at right angles to each other, in order that the lever or rod may be engaged therewith to turn the screw, and therefore raise or lower an object, this method of turning` the screw being resorted to only Where it is impossible or inconvenient to manipulate the lever or crank, hereinafter referred to.

23 designates a shaft journaled near one end in the opening 6 and formed With a Wormthread 24, engaging the peripherally--grooved teeth of wheel 12, the grooved or curved formation of teeth 13 having a long bearing on the thread 24 in order to effecta stronger connection between said parts than if said teeth were straight.

The worm-shaft is provided with a removable collar 26, secured rigidly by a set-screw 28 and having a circular groove 27 to receive the antifriction-balls 9, and is also provided with a rigid collar 28, having an annular groove 29 to receive the antifriction-balls 30, occupying the groove 32 of the screw-plu g 31, engaging the threaded opening 7 and forming a 'journal for the corresponding end of the Worm-shaft. To secure the shaft and bearing-balls in the position described, it is necessary iirst to arrange the base or stand on its roov side, so that the bearing-balls 9 will be retained in position when placed in the groove 8. The collar 26 is then placed upon said balls and the shaft slipped down through the open.- ing 7, said collar 26, and the journal-opening 6 until its threaded end engages the threads v of the wheel,when this movementis continued byscrewing it down the proper distance. The collar 26 is then secured rigidly upon the shaft by the set-screw 23, a screw-driver (not shown) being inserted diagonally down into the chamber 4 to accomplish this purpose.

The bearing-balls 30 are now deposited carefully in the groove 29 of collar 2S, and the plug 3l is iitted upon the upwardly-projecting end of the shaft and screwed home in the The cover-plate 33,preferabl y of sheet metal and provided with a central opening through which the screw extends, is secured by bolts 34 to the top of the stand or base, so', as to cover the chambers 3 and 4 from view, and thus prevent dust or other foreign substance from obtaining access to the operative parts, and said cover-plate is formed with radial indicating-marks 35, wherewith the index-finger 36, secured to the wheel 12, isy adapted to register and indicate by its posi- ,v tion with relation to any particular indicating-,mark the height to'which the screw has been elevated.

hub extensions 26 of said wheel are the plates 27a 28a, the plate 27L by preference being prol vided with flanges 27" and 29, which project laterally and bear against the inner face of plate 28, so as to form a rectangular socket, in f which the lever 30a fits snugly but detachably.

The plates 27 and 28a are secured together by the cross-bolts 31, and projecting from plate 27a are the ears 32, to and between which is pivoted an arm 33, adapted to be f der the pressure applied would be to swing outward in the direction indicated by the arrow beyond its operative position, as shown in Fig. 5; but this difficulty is overcome by providing it with an extension 34, which bears against the plate and prevents further movement in the direction indicated. When The base or stand may now be re- In the revolution of the arm is not in use, it is folded back to the inoperative position. (Shown in Fig. 4.)

35 designates a spring which, as shown at 36a or otherwise, is secured to plate 28a and provided at its free end with a conical lug or tooth 37, projecting through an opening 3S in plate 23a and engaging one of t-he beveled or inclined surfaces 39 of the stem end of the Y-shaped dog 40, said dog being pivoted between plates 27a 28 and having its opposite arms or branches terminating in teeth 4l 42, one or the other of said teeth being held in engagement with the ratchet-wheel 24' by means of the spring-pressed lug or tooth 37 engaging the beveled surface 39 of the dog diagonally opposite to the tooth which engages the wheel. a handle 43, which is manipulated to overcome the resistance of thespring-pressed lug or tooth 37 and reverse the position of the dog, so that the movement of the lever Aor crank will cause the shaft to turn in the opposite direction. In raisingv the lever `after each down or power stroke the operative tooth of the dog must of course slip back over one or more teeth of the ratchet, and toaccommodate this pivotal action of the dog the spring-pressed lug or tooth 37 must yield, pressure being applied upon the same by the opposing beveled surface 39 of the dog sliding under the lug or'tooth; butin thisaction the point of said lug or tooth never becomes totally disengaged from said beveled surface, because the operative tooth clears the periphery of the ratchet-wheel tooth just about the same time the said lug or tooth reaches the i upper edge of said beveled surface, an-d as Upon one end of the shaft 23 a ratchet-l wheel 24L is secured by means of a key 25L or equivalent means, and journaled upon the the operative tooth of the dog clears the tooth of the ratchet-wheel the spring-pressed lug or tooth by pressure on said beveled surface instantly causes the pivotal oscillation .of the.

dog and snaps its said tooth into the registering notch of the ratchet-wheel. When the opposite tooth of the dog is engaged with the ratchet-wheel, the spring-pressed lug or tooth 37 is in engagement with the beveled surface 39 at the opposite 'side of the stem of the dog and acts to hold tooth 42 against the ratchetwheel, as will be readily understood.

In the practical operation of this liftingjack it is sometimes found necessary to lift an object which rests squarely upon the ground and under which the jack cannot be conveniently placed.` To accommodate this class of objects, I provide the jack with adetachable hanger 44, which bears against the side or the swelling 1 on the side of the base or stand for the purpose of causing the jack `to sustain the weight endwise without any lateral or twisting strain upon the screw. This hanger is provided at its lower end with a 4foot 45 to underlie the object to'be lifted and at its upper end with an arm 46 to rest upon the head of the jack, said arm being formed with opposite hooks 47 to embrace the sides and the under side of the head. The hanger is fitted The dog is provided with IOO IIO

upon the screw-head in an obvious manner and is formed with a brace-rib under the arm 46. Supposing the parts to be arranged as shown, it is only necessary to manipulate the lever or crank, as the case may be, in the proper direction to rotate the worm-wheel and cause the screw to move upward or downward, the weight upon the screw obviously causing the latter to ascend or descend without any twisting or turning movement, it being clear that the tendency of the screw under the rotary action of the wheel would be to turn if not carrying a load. The fact that the Worm-shaft and the worm-wheel are both mounted on ballbearings reduces the friction on said parts to the minimum, and in practice it is found that an enormous load can be elevated by this jack with but a small expenditure of force on the part of the operator, and a single supply of lubricant, such as castor-oil, keeps this jackin perfect working order foralong period of time.

From the above description it will be apparent that I have produced a lifting-jack which embodies the features enumerated as desirable in the statement of invention, and it is to be understood, of course, that changes in the detail construction, arrangement, form, or proportion of the parts will not be considered a departure from the spirit and scope of the invention.

Having thus described the invention,what I claim as new, and desire to secure by Letters Patent, isn

1. In a lifting-jack, a base or stand, a screw therein, a worm-wheel therein engaging the screw, a shaft having a worm-thread engagthrough said opening and engaging said dog, v

and a handle 30fL fitting between the plates and flanges 27a and 29a, substantially as described.

2. In a lifting-jack, a base or stand, a screw therein, a worm-wheel therein engaging the screw, a shaft having a worm-thread engaging said wheel, a'ratchet-Wheel carried on said shaft, and a lever journaled on said shaft, consisting of the plate 27, a plate 2Sa secured to the plate 27, a dog pivoted between said plates and provided with a pair of teeth, a pawl carried by plate 28a and engaging said dog to hold one of its teeth or the other in en-4 gagement with the ratchet-wheel, lugs 32EL projecting from plate 27, and a lever or handle 33E pivoted to and between said lugs, and

provided with an extension 34 adapted to bear against plate 27n when the handle eX- tends at about a right angle from said plate 27, substantially as and for the purpose set forth.

In testimony whereof I affix my signature in the presence of two witnesses.

.TACK CALDWELL, Witnesses:

M. R. REMLEY, HELEN Roneuns 

